After more than six years of R&D, the USDA Forest Products Laboratory and the Univ. of Wisconsin, both in Madison, have developed a composite for high-strength profiles made of 50/50 and 40/60 blends of cow manure and HDPE or PP. The manure is a refined residue left after extraction of methane from the manure in a commercial digester. It is then put through a pellet mill and dried. (Several hundred digester plants have sprung up in recent years to remove methane from cow manure.) When compounded, the dried manure residue reportedly has little odor left. It may be useful as a reinforcing filler in plastics because it contains substantial amounts of organic fibers. PNC Products LLC in St. Louis ran compounding trials last December on twin-screw extruders at Entek Extruders’ lab in Lebanon, Ore., producing fiber-filled composite pellets for sampling. Potential applications are panels for portable toilets, boards for farm enclosures, and even injection molded auto parts like distributor caps, which are being tested. PP with 40% manure fiber has a flex modulus of 3.68 GPa and modulus of rupture of 41.8 GPa. With 50% manure, flex modulus is 3.81 GPa and modulus of rupture is 36.8 GPa. A 50% manure composite with 2% compatibilizer shows flex modulus dropping to 3.77 GPa, but modulus of rupture rises to 48.6 GPa, which is comparable to 50/50 PP and pine flour. (703) 402-3261 • www.pncproducts.org (541) 259-1068 • www.entekextruders.com
250 N. Hansard Ave. P.O. Box 39
Lebanon, OR 97355
Phone (541) 259-1068 Fax (541) 259-8018
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